Many processor-based devices have various inactivity timeout rules which trigger certain events based on the length of time since the user last appeared active. An inactivity timeout is a predefined amount of time that is assumed to accurately signal that the device is no longer in use. For example, most display devices have a dimming feature which will dim the display in order to save power. Typically, this dimming will take place on a system-wide basis and will be enacted based on user interaction and a time delay. A typical computer screen saver is one well-known example of this feature. However, many other devices, such as gaming consoles, mobile phones, or tablet devices also have analogous dimming features.
This simple time-based method does not account for interactions a user may be having with the display device without using an input device. For example, a user may be reading a document on the display or watching a video. These are two activities which are time-consuming but do not necessarily require user input. If the device is set to enter a power saving mode, the user may be interrupted if the user is taking a long time to read the screen or watch the video.